Model Based Systems of Systems Engineering Fran McCafferty Principal Systems Engineer fmccafferty@vitechcorp.com 1
System of Systems v System of Subsystems The major distinction between systems as elements of an SoS and subsystems as elements of a system is therefore that the SoS comprises elements (systems) that are optimised for their own purposes before joining the SoS, whereas the system comprises elements (subsystems) that are optimised for the system s purpose (not necessarily their own). Faulconbridge, Ian; Ryan, Michael. Introduction to Systems Engineering (Kindle Locations 268-277). Argos Press Pty Ltd. Kindle Edition. 2
System of Systems vs. System of Subsystems Both comprise elements that are interconnected, but: System of Systems System of Subsystems Elements are systems in their own Not independent right, managerially and operationally Only exist to serve the parent system independent Invariably sub-optimal Elements have been optimized for their own purpose 3
What s your definition of a system? Fundamental Concepts A System: Performs a function, transforming inputs to outputs Is a collection of interacting components with a common goal A Subsystem: Can be considered a system Therefore, the analysis and specification of a system is hierarchical and iterative - System - Subsystem - Component -... System of Systems System Sub-System Component 4
System of Systems Multiple Cooperating Systems Multiple and often geographically distributed organizations Multiple design teams Single Large System What was it optimized for? Cost Schedule Legacy technology System partition basis Functionality Geography Organization expertise 5
Example: Radar Air and Surface Search Radar Restoration Program How does a program office support a critical system for extended periods of time from a maintenance and upgrade perspective? What are the options? Replace the entire system Design from scratch Implement an existing system Maintain the existing system Replace broken/failed components Perform capability upgrades 6
What are the options? 7
Mission Engineering System of Systems Engineering Our world is far from static, so what do we do? Do we need to evolve? Probably. Do we understand the problem? Can we afford to evolve? How much evolution can we stand? 8
System of Systems US Navy Restoration Example Single Large System What was it optimized for? Cost Schedule Legacy technology System partition basis Functionality Geography Organization expertise 9
MBSE Activities Timeline + Reverse Engineering Find the Top 1.Define System Boundary 8. Update System Boundary 7. Derive As-Built 7f. Modify Reqts & System Reqts Arch. Constraints 6. Derive As-Built 6a. Modify System System Threads Threads 5. Aggregate to As-Built System Behavior 4. Derive As-Built Behavior of Components 3. Capture Component Hierarchy 2. Capture Interfaces SCHEDULE 5a. Modify & Decompose System Behavior 4a. Allocate Behavior to Components 3a. Refine Component Hierarchy 2a. Define Interfaces 9. Select Design Reconcile 10. Perform Effectiveness & Feasibility Analyses 11. Capture Error Detection, Resource, & Recovery Behavior 12. Develop Test Plans 13. Generate Documentation and Specifications 10
So what do you do? What is in the scope of the project, and who says so? Clearly define the boundaries Ensure the subsystems are fully defined from a capability, physical characteristics, and most importantly, know the interfaces. Interface definition means knowing what information traverses the subsystem boundary. What are the physical, logical, and functional characteristics? Manage the complexity What changes? How do we know? Answer: Systems engineer it, model it! 11
So what do you do? If we reverse engineer the existing system, we know the critical capabilities and constraints. Capture the legacy requirements Model Physical Architecture Behavior functions, information, control, and timing Interfaces Links Constraints Now we know the baseline. Answer: Systems engineer it, model it! 12
Do the analysis Ask What does the upgraded system have to do? How do we partition? At what level do we want to compete acquisition? Apply Model Based Systems Engineering 13
Multi-Project Roadmap Partitions Rx Tx Rx Antenna Why, and benefits v. Mega Project Strata, just boundary not down to nth layer, thin model, black box, white box, Integration Perspective, contractual boundaries, defining lower level.let s have a look Processor Projects Hierarchy Radar System of Systems Antenna Rx Tx 14
Model the s Use what you have in SSS, IRS, ICD 3.2 CHARACTERIST ICS 3.2.1 refined by SSS 3.2 System requirements 3.7 Major subsystems requirements 3.2.1.4 3.2.1.4 refined by Transmit State PERFORMANCE 3.2.1.5 refined by Operating Environments refined by refined by refined by 3.2.1.4.1 3.2.1.5.2 Transmit State Normal Mode Clutter Diagram: CORE-generated requirements hierarchy diagram refined by refined by refined by 3.2.1.5.2.1 3.2.1.5.2.2 3.2.1.5.2.3 Rain Clutter Sea Clutter Distributed Land Clutter refined by refined by refined by 3.2.1.5.2.4 3.2.1.5.2.5 3.2.1.5.2.6 Chaff Discrete Clutter Bird Clutter 15
Model the Architecture Using Components, Establish Interfaces/Links Use what you have in SSS, IRS, ICD SSS SHIP'S INPUTS (SYNCHRO) Ships Power TDS/FCS Beam Stabilization Pedestal Assembly 3.2 System requirements 3.7 Major subsystems requirements SECONDARY VIDEO #2 SECONDARY VIDEO #1 SYNCHRO DISTRIBUTION AN/SPQ-9B RADAR VIDEO DISTRIBUTION JUNCTION Microwave Distribution System Antenna Unit Antenna Unit Output Signals Antenna Assembly REMOTE PP'S Environment (Weather) Antenna Unit Input Signals PRIMARY VIDEO OTHER DIGITAL INTERFACES (TBD) JUNCTION BOX 16
Antenna Project Diagram: CORE-generated structure block diagram Separate projects maintains system context and subsystem boundaries. Antenna Unit Link projects through components. Antenna Assembly Antenna Unit Input Signals Antenna Unit Output Signals Beam Stabilization Microwave Distribution System Pedestal Assembly Use built from relationship. Recall, a context function, is automatically generated, + can also be a decomposition of the radar. Pedestal Gyro Antenna Alignment Pedestal Mounting Slip Rings 17
Create Multiple Projects System Project SoS for Antenna Unit 18
Tiered Projects Separate projects Maintains system context Identifies subsystem boundaries Link projects through components Use built from relationship Recall, a context function, is automatically generated, + can also be a decomposition of the radar. Specifications linked to specific project System Specification Antenna Unit Subsystem Spec (SSS, or in the old days, B Spec) Allows for the Antenna Unit to be easily severable, Supports subsystem level acquisition strategies, Provides context for technology insertion / and sustainment 19
Summary System of Systems and Mission Engineering similarities. Separate but linked projects provide context and linkage. Independent projects enable clearly understandable subsystems. Higher fidelity of requirements, traceable but not overwhelming Clear interfaces between subsystems Physical hierarchy shows transition from one design/support group to another Promotes separation of concerns, while maintaining traceability and consistency PMO Support Enables PMO to generate RFP from models Radar Restoration is considering requiring a model as part of proposal package 20
For more information: Vitech website: Blog: Presenter: http://www.vitechcorp.com/ http://community.vitechcorp.com/home/ fmccafferty@vitechcorp.com 540.951.3322 x304 or 856.217.9963 We invite your comments and questions. THANK YOU! 21